In recent years, diketopyrrolopyrroles (DPPs) have become one of the Extensively studied organic building blocks of oligomers and polymers having promising optoelectronic properties, especially in solar cells. Reference is made to D. Chandran and Kwang-Sup Lee, Macromolecular Research 21 (2013) 272.
US2011/0004004 relates to compounds of the formula
and their use as organic semiconductor in organic devices, like diodes, organic field effect transistors and/or a solar cells.
WO2011/144566 relates to polymers comprising one or more (repeating) unit(s) of the formula
or a polymer of formula
wherein A is a group of formula
and their use as organic semiconductor in organic devices, especially in organic photovoltaics (solar cells) and photodiodes, or in a device containing a diode and/or an organic field effect transistor.
Daniel T. Gryko et al. Organic Letters 14 (2012) 2670 disclose a synthetic approach to π-expanded diketopyrrolopyrroles. A three-step strategy appears to be very general and starts with the preparation of diketopyrrolopyrroles followed by N-alkylation with bromoacetaldehyde diethyl acetal and electrophilic aromatic substitution. The final reaction regioselectively furnishes fluorescent dyes.
WO2013/092474 (PCT/EP2012/075762), which enjoys an earlier priority date than the present invention, but has been published after the priority date of the present invention, relates to compounds of formula (III):
where Ar denotes a homo- or heteroaromatic system.
PCT/EP2014/054060, which enjoys an earlier priority date than the present invention, but has been published after the priority date of the present invention, relates to novel compounds of formula
that can be used as heterocyclic dyes of unique structure and properties. These compounds can be obtained in a three-step synthesis from simple substrates.